The present invention relates to a switch unit which is improved in the construction to give a click to a switching control element which is operated to rock.
Conventionally, there have been switch units which are configured as is shown in FIG. 8. In those switch units, a switch case 1 is made up of a case lower body 1a and a case upper body 1b, and a switching control element 2 is supported on the case upper body 1b of the two bodies in such a manner as to rock clockwise and counterclockwise as viewed in the figure on a shaft portion 3. The switching control element 2 has a cylindrical portion 4 below the shaft portion 3, and a spring 5 and a clicking piece 6 are accommodated in the cylindrical portion 4.
A circuit board 7 is provided in such a manner as to be held between the case lower body 1a and the case upper body 1b, and pairs of stationary contacts 8, 9 are provided on the circuit board 7. In addition, a sheet 12, which is made of, for example, rubber, is provided, and this rubber sheet 12 has movable portions 12a, 12b which have, respectively, movable contacts 10, 11 which are adapted to be connected to and disconnected from the stationary contacts 8, 9, respectively.
A hole 13 is formed in a portion in the circuit board 7 which lies between the stationary contacts 8, 9, and the cylindrical portion 4 of the switching control element 2 passes through this hole 13. In addition, clicking recessed portions 14, 15 are formed on a bottom surface portion of the case lower body 1a which is where the cylindrical portion 4 ends which has passed through the hole 13, and a clicking piece 6 is brought into engagement with one (the recessed portion 14 in a state shown in the figure) of the clicking recessed portions so formed by virtue of a biasing force applied by the spring 5.
In this configuration, when the switching control element 2 is operated to rock clockwise, the movable portion 12b of the sheet 12 is pushed by the switching control element 2 to thereby bring the movable contact 11 into contact with the stationary contacts 9, whereas when the switching control element 2 is operated to rock counterclockwise, the movable portion 12a of the sheet 12 brings the movable contact 10 into contact with the stationary contacts 8. In addition, every time the switching control element 2 is operated to rock clockwise and counterclockwise in the figure, the clicking piece 6 moves to the recessed portion 14 and the recessed portion 15 in such a way as to reciprocate between the two recessed portions, and during this movement, the clicking piece 6 rides over an angular portion 16 to thereby impart a click to the rocking operation of the switching control element 2 (refer to, for example, JP-UM-A-6-50204).
In the case of the conventional switch unit, the clicking piece 6 and the spring 5 were necessary to impart the click to the rocking operation of the switching control element 2, and the number of components was increased by such an extent that the components concerned were involved and hence, the production costs were increased accordingly.